Ultra high frequency tube of the resonator type



y 1947- H. J. MCCARTHY 2,423,426

ULTRA HIGH FREQUENCY TUBE OF THE RESONATOR TYPE F iled Nov. 1:5, 194s INVENTOR. HENRY J 17 CARTHY ATTORNEY Patented July 1, 1947 ULTRA HIGH FREQUENCY TUBE OF THE RESONATOR TYPE Henry J. McCarthy,

Sylvania Danvers, Mass, assignor to Electric Products Inc., Salem, Mass,

a corporation of Massachusetts Application November 13, 1943, Serial No. 510.225

3 Claims.

This invention relates to radio tubes and similar devices and particularly to tubes for automatic switching from receiving to transmitting on the same antenna, particularly at ultra-high frequencies.

Such tubes often employ a copper resonating circuit extending into an insulating sealed tube of material such as glass and filled with a gas comprising water vapor. The latter gradually disappears or cleans up during operation, reducing the life of the tube.

An object and advantage to increase the tube life by clean up.

A feature of the invention is the use of a protective layer over the copper parts otherwise exposed to the water vapor inside the tube.

Other features, objects and advantages of the invention will be apparent from the following specification, taken in connection with the accompanying drawing, in which:

Figure 1 is a general external view of the device of my invention; and

Figure 2 is an internal view of the device.

In the figures, the glass tube I has sealed into it a gas comprising water vapor, and hydrogen at a pressure of a few millimeters. For example, the water vapor may have a pressure of 7 millimeters of mercury, and the hydrogen mm. The copper discs 2, 3 are sealed through the sides of the glass tube 1, and a copper frustrum 4, 5 of a cone extends from each disc toward and in register with the other. The electrode 6 is sealed through the top of the tube and extends to the space near the gap between the two frustra 4, 5, which are spaced from each other. The copper discs are connected together by a metal ring I joining their outer circumferences. The lead-in wires 8, 9 are the axial conductors of a coaxial cable whose outer conductors are tubes II], II, The axial conductor of the cable is formed into a loop l2 at the open end of the cable where the cable is joined to the interior of the ring 1. The end of the loop is of course, connected to the ring I in the usual manner to provide coupling of the invention is preventing such between the coaxial cable and the resonant circuit of which the ring 1 is a part.

The surface of the copper discs 4, 5, and their frustro-conical portions 4, 5, is covered by a protective layer E3 of material which resists oxidation, such as the black oxide of copper itself. This non-oxidizing layer prevents reaction between -the water vapor and the copper and thus prolongs the life of the water vapor and of the tube. Previous tubes before my invention have used bright, shiny unprotected copper discs. One such tube, for example, is shown in co-pending application Serial No. 495,752 filed July 7, 1943, by Nathaniel Rochester, which also shows a circuit for such a tube.

What I claim is:

1. An electronic tube comprising a metallic resonator, an atmosphere within the tube having several millimeters of pressure of water vapor and a coating on the surfaces of said resonator within the tube thereof by said water vapor.

2. The combination of claim 1 in which the resonator is copper and the coating is black oxide of copper.

3. An electronic tube comprising a metallic copper resonator, an atmosphere within said tube containing water vapor, and a coating of black oxide of copper on said resonator within said tube.

HENRY J. MCCARTHY.

REFERENCES CITED The following references are of record in the and which prevents oxidation 

